Tests to detect suboptimal effort during neuropsychological assessment are becoming widely used in clinical practice based on their reported insensitivity to cognitive dysfunction. This study aimed to examine the performance of individuals with working age dementia on six tests of effort, the MSVT, NV-MSVT, TOMM, Rey 15, Rey Dot Counting and Coin in the Hand, in order to determine whether cognitive functioning adversely influences test performance. 42 participants who received a diagnosis of dementia before the age of65 completed measures of emotional and cognitive functioning and six effort tests. The results demonstrate that cognitive functioning, in particular the domain ofNew Learning, is significantly related to effort test performance. Participants with mild dementia performed significantly better on all six effort tests than those classified as having moderate/severe dem